Monolayer cultures of human prostatic carcinoma cells will be established. These lines will be isolated directly from primary cell suspensions of prostatic specimens by clonal techniques. They will be characterized with respect to clonal plating efficiency, growth rate, morphology, karyotype, oncogenicity, sterility, and tartrate-inhibitible acid phosphatase activity. Selected lines will be preserved for future use in liquid nitrogen. These lines will serve as a model system to test the efficiency of antitumor agents, to determine tumor cell response to hormones and for biochemical and genetic studies.